Method of manufacturing a fluid-filled chamber with a tensile element

ABSTRACT

A method of manufacturing a fluid-filled chamber with a tensile element includes manufacturing a tensile element and incorporating the tensile element into a chamber. A first material layer, a second material layer, and a spacing structure having a plurality of support portions and a plurality of gaps may be stacked. The material layers may be located on either side of the spacing structure or on one side of the spacing structure. A strand may be stitched through the gaps to join the material layers and to form the tensile element. The spacing structure may be removed, and the first material layer may be spaced from the second material layer such that segments of the strand extend between the material layers. The tensile element may then be secured to opposite interior surfaces of an outer barrier, and the outer barrier may be pressurized to place the strand in tension.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.16/107,800, filed Aug. 21, 2018, which is a Continuation of U.S. patentapplication Ser. No. 15/133,342, filed Apr. 20, 2016, which is aContinuation of U.S. patent application Ser. No. 13/839,747, filed Mar.15, 2013, the entire contents of which are incorporated herein byreference.

BACKGROUND

Articles of footwear generally include two primary elements, an upperand a sole structure. The upper is formed from a variety of materialelements (e.g., textiles, foam, leather, and synthetic leather) that arestitched or adhesively bonded together to form a void on the interior ofthe footwear for comfortably and securely receiving a foot. An ankleopening through the material elements provides access to the void,thereby facilitating entry and removal of the foot from the void. Inaddition, a lace is utilized to modify the dimensions of the void andsecure the foot within the void.

The sole structure is located adjacent to a lower portion of the upperand is generally positioned between the foot and the ground. In manyarticles of footwear, including athletic footwear, the sole structuregenerally incorporates an insole, a midsole, and an outsole. The insole,which may be located within the void and adjacent to a lower surface ofthe void, is a thin compressible member that enhances footwear comfort.The midsole, which may be secured to a lower surface of the upper andextends downward from the upper, forms a middle layer of the solestructure. In addition to attenuating ground reaction forces (i.e.,providing cushioning for the foot), the midsole may limit foot motionsor impart stability, for example. The outsole, which may be secured to alower surface of the midsole, forms at least part of theground-contacting portion of the footwear and is usually fashioned froma durable and wear-resistant material that includes texturing to improvetraction.

Generally, the midsole is primarily formed from a foamed polymermaterial, such as polyurethane or ethylvinylacetate, that extendsthroughout a length and width of the footwear. In some articles offootwear, the midsole may include a variety of additional footwearelements that enhance the comfort or performance of the footwear,including plates, moderators, fluid-filled chambers, lasting elements,or motion control members. In some configurations, any of theseadditional footwear elements may be located between the midsole andeither of the upper and the outsole, may be embedded within the midsole,or may be encapsulated by the foamed polymer material of the midsole,for example. Although many midsoles are primarily formed from a foamedpolymer material, fluid-filled chambers or other non-foam structures mayform part of or a majority of some midsole configurations.

Various techniques may be utilized to form fluid-filled chambers forarticles of footwear or other products, including a two-film technique,a thermoforming technique, and a blowmolding technique, for example. Inthe two-film technique, two separate polymer sheets are bonded togetherat specific locations. The thermoforming technique is similar to thetwo-film technique in that two polymer sheets are bonded together, butalso includes utilizing a heated mold to form or otherwise shape thepolymer sheets. In the blow-molding technique, a parison formed from amolten or otherwise softened polymer material is placed within a moldhaving a cavity with the desired configuration of the chamber.Pressurized air induces the polymer material to conform to surfaces ofthe cavity. The polymer material then cools and retains the shape of thecavity, thereby forming the chamber.

Following each of the techniques discussed above, the chambers arepressurized. That is, a pressurized fluid is injected into the chambersand then sealed within the chambers. One method of pressurizationinvolves forming inflation conduits in residual portions of the polymersheets or the parison. In order to pressurize the chambers, the fluid isinjected through the inflation conduits, which are then sealed. Theresidual portions of the polymer sheets or the parison, including theinflation conduits, are then trimmed or otherwise removed tosubstantially complete manufacture of the chambers.

SUMMARY

Various features of fluid-filled chambers and methods of manufacturingfluid-filled chambers are disclosed below. In one configuration, amethod of manufacturing a fluid-filled chamber comprises steps ofstacking, stitching, positioning, securing, and pressurizing. In onestep, the method includes stacking a first material layer, a secondmaterial layer, and a spacing structure having a plurality of supportportions. In another step, the method includes stitching between thesupport portions with a strand to join the first material layer to thesecond material layer and to form a tensile element from the firstmaterial layer, the second material layer, and the strand. In anotherstep, the method includes positioning the tensile element within anouter barrier. In another step, the method includes securing the firstmaterial layer and the second material layer to opposite interiorsurfaces of the outer barrier. In another step, the method includespressurizing the outer barrier to place the strand in tension.

In another configuration, a method of manufacturing a fluid-filledchamber comprises steps of locating, stitching, positioning, heating andcompressing, sealing, and pressurizing. In one step, the method includeslocating a spacing structure between a first material layer and a secondmaterial layer, the spacing structure having a plurality of supportportions separated by a plurality of gaps. In another step, the methodincludes stitching through the gaps with at least one strand to join thefirst material layer to the second material layer and to form a tensileelement from the first material layer, the second material layer, andthe strand. The tensile element has a plurality of segments of thestrand that extend between the first material layer and the secondmaterial layer. In another step, the method includes positioning thetensile element between a first polymer sheet and a second polymersheet. In another step, the method includes heating and compressing thefirst polymer sheet and the second polymer sheet to secure the firstpolymer sheet to the first material layer and to secure the secondpolymer sheet to the second material layer. In another step, the methodincludes sealing the first polymer sheet to the second polymer sheet tocreate a peripheral bond and an interior void. In another step, themethod includes pressurizing the interior void to place the segments ofthe strand in tension.

In a further configuration, a method of manufacturing a fluid-filledchamber comprises steps of locating, stitching, removing, spacing,incorporating, and pressurizing. In one step, the method includeslocating a first material layer between a spacing structure and a secondmaterial layer, the first material layer being in contact with thesecond material layer, and the spacing structure having a plurality ofsupport portions. In another step, the method includes stitching with atleast one strand both between the support portions and over at least onesupport portion to join the first material layer to the second materiallayer and to form a tensile element from the first material layer, thesecond material layer, and the strand. In another step, the methodincludes removing the spacing structure. In another step, the methodincludes spacing the first material layer from the second material layerto position a plurality of segments of the strand to extend between thefirst material layer and the second material layer. In another step, themethod includes incorporating the tensile element into an interior voidof a barrier. In another step, the method includes pressurizing theinterior void of the barrier to place the segments of the strand intension.

The advantages and features of novelty characterizing aspects of theinvention are pointed out with particularity in the appended claims. Togain an improved understanding of the advantages and features ofnovelty, however, reference may be made to the following descriptivematter and accompanying figures that describe and illustrate variousconfigurations and concepts related to the invention.

FIGURE DESCRIPTIONS

The foregoing Summary and the following Detailed Description will bebetter understood when read in conjunction with the accompanyingfigures.

FIG. 1 is a lateral side elevational view of an article of footwearincorporating a fluid-filled chamber.

FIG. 2 is a medial side elevational view of the article of footwear.

FIG. 3 is a cross-sectional view of the article of footwear, as definedby section line 3 in FIG. 1.

FIG. 4 is a perspective view of the chamber.

FIG. 5 is an exploded perspective view of the chamber.

FIG. 6 is a top plan view of the chamber.

FIG. 7 is a lateral side elevational view of the chamber.

FIGS. 8A-8C are cross-sectional views of the fluid-filled chamber, asrespectively defined by section lines 8A-8C in FIG. 6.

FIG. 9 is a perspective view of a spacing structure used in a processfor manufacturing a tensile element.

FIGS. 10A-10D are schematic perspective views depicting the process formanufacturing the tensile element.

FIGS. 11A-11F are schematic perspective views depicting another processfor manufacturing the tensile element.

FIG. 12 is a perspective view of a mold that may be utilized in aprocess for manufacturing a chamber including the tensile element.

FIG. 13A-13D are perspective views depicting the process formanufacturing the chamber.

FIGS. 14A-14D are schematic cross-sectional views of the process formanufacturing the chamber, as respectively defined by section lines14A-14D in FIGS. 13A-13D.

FIGS. 15A-15H are perspective views corresponding with FIG. 9 anddepicting additional configurations of the spacing structure.

FIGS. 16A-16C are perspective views corresponding with FIG. 10D anddepicting additional configurations of the process for manufacturing thetensile element.

FIGS. 17A-17G are cross-sectional views corresponding with FIG. 8A anddepicting additional configurations of the chamber.

FIGS. 18A-18C are cross-sectional views corresponding with FIG. 8C anddepicting additional configurations of the chamber.

DETAILED DESCRIPTION

The following discussion and accompanying figures disclose variousconfigurations of fluid-filled chambers with tensile elements andmethods for manufacturing the chambers. Although the chambers aredisclosed with reference to footwear having a configuration that issuitable for running, concepts associated with the chambers may beapplied to a wide range of athletic footwear styles, includingbasketball shoes, cross-training shoes, football shoes, golf shoes,hiking shoes and boots, ski and snowboarding boots, soccer shoes, tennisshoes, and walking shoes, for example. Concepts associated with thechambers may also be utilized with footwear styles that are generallyconsidered to be non-athletic, including dress shoes, loafers, andsandals. In addition to footwear, the chambers may be incorporated intoother types of apparel and athletic equipment, including helmets,gloves, and protective padding for sports such as football and hockey.Similar chambers may also be incorporated into cushions and othercompressible structures utilized in household goods and industrialproducts. Accordingly, chambers incorporating the concepts disclosedherein may be utilized with a variety of products.

General Footwear Structure

An article of footwear 10 is depicted in FIGS. 1-3 as including an upper20 and a sole structure 30. For reference purposes, footwear 10 may bedivided into three general regions: a forefoot region 11, a midfootregion 12, and a heel region 13. Forefoot region 11 generally includesportions of footwear 10 corresponding with the toes and the jointsconnecting the metatarsals with the phalanges. Midfoot region 12generally includes portions of footwear 10 corresponding with the archarea of the foot. Heel region 13 generally includes portions of footwear10 corresponding with rear portions of the foot, including the calcaneusbone. Regions 11-13 are not intended to demarcate precise areas offootwear 10. Rather, regions 11-13 are intended to represent generalareas of footwear 10 to aid in the following discussion. In addition tobeing applied to footwear 10, regions 11-13 may also be applied to upper20, sole structure 30, and individual elements thereof.

Footwear 10 also includes a lateral side 14 and a medial side 15. Moreparticularly, lateral side 14 corresponds with an outside area of thefoot (i.e. the surface that faces away from the other foot), and medialside 15 corresponds with an inside area of the foot (i.e., the surfacethat faces toward the other foot). Lateral side 14 and medial side 15also extend through each of regions 11-13 and correspond with oppositesides of footwear 10. As with regions 11-13, sides 14 and 15 representgeneral areas of footwear 10 to aid in the following discussion, and mayalso be applied to upper 20, sole structure 30, and individual elementsthereof, in addition to being applied to footwear 10.

Upper 20 is depicted as having a substantially conventionalconfiguration incorporating a plurality of material elements (e.g.,textile, foam, leather, and synthetic leather) that are stitched,adhered, bonded, or otherwise joined together to form an interior voidfor securely and comfortably receiving a foot. The material elements maybe selected and located with respect to upper 20 in order to selectivelyimpart various properties to upper 20, such as durability,air-permeability, wear-resistance, flexibility, and comfort. An ankleopening 21 in heel region 13 provides access to the interior void. Inaddition, upper 20 may include a lace 22 that is utilized in aconventional manner to modify the dimensions of the interior void,thereby securing the foot within the interior void and facilitatingentry and removal of the foot from the interior void. Lace 22 may extendthrough apertures in upper 20, and a tongue portion of upper 20 mayextend between the interior void and lace 22. Upper 20 may alsoincorporate a sockliner 23 that is located within the void in upper 20and adjacent a plantar (i.e., lower) surface of the foot to enhance thecomfort of footwear 10. Given that various aspects of the presentapplication primarily relate to sole structure 30, upper 20 may exhibitthe general configuration discussed above or the general configurationof practically any other conventional or non-conventional upper.Accordingly, the overall structure of upper 20 may vary significantly.

Sole structure 30 is secured to upper 20 and has a configuration thatextends between upper 20 and the ground. In effect, therefore, solestructure 30 is positioned to extend between the foot and the ground. Inaddition to attenuating ground reaction forces (such as by providingcushioning for the foot), sole structure 30 may provide traction, impartstability, and limit various foot motions, such as pronation.

The primary elements of sole structure 30 are a midsole 31 and anoutsole 32. Midsole 31 may incorporate a polymer foam material, such aspolyurethane or ethylvinylacetate. Midsole 31 may also incorporate afluid-filled chamber 33. In addition to the polymer foam material andchamber 33, midsole 31 may incorporate one or more other footwearelements that enhance the comfort, performance, or ground reaction forceattenuation properties of footwear 10, including plates, moderators,lasting elements, or motion control members.

Outsole 32, which may be absent in some configurations of footwear 10,is depicted as being secured to a lower surface of midsole 31 and formsat least part of a ground-contacting surface of footwear 10. Outsole 32may be formed from a rubber material that provides a durable andwear-resistant surface for engaging the ground. In addition, outsole 32may also be textured to enhance the traction (i.e., friction) propertiesbetween footwear 10 and the ground. In various other configurations offootwear 10, and depending upon the manner in which midsole 31incorporates the polymer foam material, chamber 33, or both, outsole 32may be secured to the polymer foam material alone, to chamber 33 alone,or to both the polymer foam material and chamber 33. In someconfigurations, outsole 32 may be absent from footwear 10.

Chamber 33 is depicted as having a shape that fits within a perimeter ofmidsole 31 and is depicted as being primarily located in heel region 13.Accordingly, when the foot is located within upper 20, chamber 33extends under a heel area of the foot (for example, under a calcaneusbone of the wearer) in order to attenuate ground reaction forces thatare generated when sole structure 30 is compressed between the foot andthe ground during various ambulatory activities, such as running andwalking. In various other configurations, chamber 33 may extend throughalternate portions of footwear 10. For example, chamber 33 may extendonly through forefoot region 11, or only through midfoot region 12, orthrough substantially all of footwear 10 (i.e., from forefoot region 11to heel region 13 and also from lateral side 14 to medial side 15).Alternatively, chamber 33 may extend only through lateral side 14 offootwear 10, or only through medial side 15 of footwear 10. Chamber 33may also extend through any combination of regions and sides. In otherwords, in various configurations, chamber 33 may extend through anyportion or portions of footwear 10.

Chamber 33 is also depicted as being substantially surrounded by orentirely encapsulated within a polymer foam material of midsole 31 andsecured to the polymer foam material. In various other configurations offootwear 10, however, midsole 31 may otherwise incorporate chamber 33.For example, chamber 33 may be partially encapsulated within the polymerfoam material of midsole 31, or may be above the polymer foam material,or may be below the polymer foam material, or may be between layers orregions of one or more polymer foam materials. As an example, portionsof chamber 33 may form an upper or lower surface of midsole 31. In someconfigurations, the polymer foam material of midsole 31 may be absentand chamber 33 may be secured to both upper 20 and outsole 32.

Moreover, while a sidewall of midsole 31 is depicted as being formedsubstantially entirely by the polymer foam material of midsole 31, thesidewall may be otherwise formed in various other configurations offootwear 10. For example, the sidewall of midsole 31 may be formedpartially by the polymer foam material of midsole 31 and partially byportions of chamber 33. That is, one or more portions of chamber 33 maybe exposed on sides 14 and 15 to form one or more portions of thesidewall. In further configurations, the sidewall of midsole 31 may besubstantially entirely formed by exposed portions of chamber 33.

Additionally, in various configurations, chamber 33 may contact or besecured to one or more other footwear elements within midsole 31, suchas plates, moderators, lasting elements, or motion control members.Accordingly, the overall shape of chamber 33 and the manner in whichchamber 33 is incorporated into footwear 10 may vary significantly.

Furthermore, although chamber 33 is depicted and discussed as being asealed chamber within footwear 10, chamber 33 may also be a component ofa fluid system within footwear 10. More particularly, pumps, conduits,and valves may be joined with chamber 33 to provide a fluid system thatpressurizes chamber 33 with air from the exterior of footwear 10 or areservoir within footwear 10. In some configurations, chamber 33 mayincorporate a valve or other structure that permits an individual, suchas a wearer, to adjust the pressure of the fluid. As examples, chamber33 may be utilized in combination with any of the fluid systemsdisclosed in U.S. Pat. No. 7,210,249 to Passke, et al. and U.S. Pat. No.7,409,779 to Dojan, et al, including fluid systems that vary thepressure within chamber 33 depending upon, for example, the runningstyle or weight of the wearer.

Chamber Configuration

Chamber 33 is depicted individually in FIGS. 4-8C as having asubstantially flat configuration that is suitable for footwearapplications. The primary elements of chamber 33 are a barrier 40 and atensile element 50.

Barrier 40 (a) forms an exterior of chamber 33, (b) defines an interiorvoid that receives both a pressurized fluid and tensile element 50, and(c) provides a durable sealed barrier for retaining the pressurizedfluid within chamber 33. An exterior surface of barrier 40 forms anouter surface of chamber 33, and an interior surface of barrier 40defines the interior void. The polymer material of barrier 40 includes(a) a first barrier portion 41 oriented toward upper 20, which may forman upper portion of barrier 40, and (b) an opposite second barrierportion 42 oriented toward outsole 32, which may form a lower portion ofbarrier 40. Barrier 40 also includes a peripheral edge 43 that extendsaround a periphery of chamber 33 and between barrier portions 41 and 42,and a peripheral bond 44 that joins a periphery of first barrier portion41 to a periphery of second barrier portion 42.

Tensile element 50 is located within the interior void and between firstbarrier portion 41 and second barrier portion 42 and is accordinglyincorporated into the interior void. Tensile element 50 includes (a) afirst material layer 51, which may be an upper layer oriented towardupper 20, (b) an opposite second material layer 52, which may be a lowerlayer oriented toward the ground, and (c) a plurality of strand segments53 in a plurality of rows 54. Material layers 51 and 52 are secured tothe interior surface of barrier 40. More particularly, first materiallayer 51 is secured to a part of an interior surface of barrier 40formed by first barrier portion 41, and second material layer 52 issecured to a part of the interior surface of barrier 40 formed by secondbarrier portion 42. As discussed in greater detail below, tensileelement 50 may be secured to barrier 40 in various ways, includingthermobonding, adhesive bonding, or both.

Strand segments 53 are portions of one or more strands (i.e., lengths ofmaterial having a generally one-dimensional structure) used to stitch,sew together, or otherwise join first material layer 51 to secondmaterial layer 52, as is discussed in greater detail below. Some strandsegments 53 extend between material layers 51 and 52, thereby extendingacross the interior void. Other strand segments 53 extend (a) across asurface of first material layer 51 facing first barrier portion 41, and(b) across a surface of second material layer 52 facing second barrierportion 42. That is, various pluralities of strand segments 53 mayextend (a) between first barrier portion 41 and first material layer 51,and (b) between second barrier portion 42 and second material layer 52.

A wide range of polymer materials may be utilized for barrier 40. Inselecting materials for barrier 40, engineering properties of thematerials (e.g., tensile strength, stretch properties, fatiguecharacteristics, dynamic modulus, and loss tangent) as well as theability of the materials to prevent the diffusion of the fluid containedby barrier 40 may be considered. When formed of thermoplastic urethane,for example, barrier 40 may have a thickness of approximately 1.0millimeter, but the thickness may range from less than 0.25 to more than2.0 millimeters, for example. In addition to thermoplastic urethane,examples of polymer materials that may be suitable for barrier 40include polyurethane, polyester, polyester polyurethane, and polyetherpolyurethane. Barrier 40 may also be formed from a material thatincludes alternating layers of thermoplastic polyurethane andethylene-vinyl alcohol copolymer, as disclosed in U.S. Pat. Nos.5,713,141 and 5,952,065 to Mitchell, et al. A variation upon thismaterial may also be utilized, wherein a center layer is formed ofethylene-vinyl alcohol copolymer, layers adjacent to the center layerare formed of thermoplastic polyurethane, and outer layers are formed ofa regrind material of thermoplastic polyurethane and ethylene-vinylalcohol copolymer. Another suitable material for barrier 40 is aflexible microlayer membrane that includes alternating layers of a gasbarrier material and an elastomeric material, as disclosed in U.S. Pat.Nos. 6,082,025 and 6,127,026 to Bonk, et al. Accordingly, chamber 33 maybe formed from various sheets of a polymer material, each of the sheetsincluding multiple layers of different polymer materials. Additionalsuitable materials are disclosed in U.S. Pat. Nos. 4,183,156 and4,219,945 to Rudy. Further suitable materials include thermoplasticfilms containing a crystalline material, as disclosed in U.S. Pat. Nos.4,936,029 and 5,042,176 to Rudy, and polyurethane including a polyesterpolyol, as disclosed in U.S. Pat. Nos. 6,013,340, 6,203,868, and6,321,465 to Bonk, et al.

A variety of processes may be utilized to manufacture chamber 33. Ingeneral, the manufacturing processes involve (a) securing a pair ofpolymer sheets, which form barrier portions 41 and 42 as well asperipheral edge 43, to tensile element 50 and (b) forming peripheralbond 44 to extend around peripheral edge 43 and join the polymer sheets.Peripheral bond 44 is depicted as being adjacent to the upper surface ofchamber 33, but in various other configurations it may be positionedbetween the upper and lower surfaces of chamber 33, or it may beadjacent to the lower surface of chamber 33. The manufacturing processmay also position tensile element 50 within chamber 33 and bond tensileelement 50 to barrier portions 41 and 42. Although substantially all ofthe thermoforming process may be performed with a mold, as described ingreater detail below, each of the various parts or steps of the processmay be performed separately in forming chamber 33. That is, a variety ofother methods may be utilized to form chamber 33.

In order to facilitate bonding between tensile element 50 and barrier40, a supplemental polymer material may be added to or incorporatedwithin tensile element 50. When heated, the supplemental polymermaterial may soften, melt, or otherwise begin to change state so thatcontact with barrier portions 41 and 42 induces material from barrier 40to intermingle or otherwise join with the supplemental polymer material.Upon cooling, therefore, the supplemental polymer material may bepermanently joined with barrier 40, thereby joining tensile element 50with barrier 40. In some configurations, thermoplastic threads or stripsmay be present within tensile element 50 to facilitate bonding withbarrier 40, as disclosed, for example, in U.S. Pat. No. 7,070,845 toThomas, et al., or an adhesive may be utilized to secure barrier 40 andtensile element 50.

Following the thermoforming process, or as part of the thermoformingprocess, a fluid may be injected into the interior void and pressurizedbetween zero and three-hundred-fifty kilopascals (i.e., approximatelyfifty-one pounds per square inch) or more. The pressurized fluid exertsan outward force upon barrier 40, which tends to separate barrierportions 41 and 42. However, tensile element 50, being secured to eachof barrier portions 41 and 42, operates to retain the intended shape ofchamber 33 when pressurized. More particularly, strand segments 53extending across the interior void are placed in tension by the outwardforce of the pressurized fluid upon barrier 40, thereby preventingbarrier 40 from expanding outward and causing chamber 33 to retain anintended shape. Whereas peripheral bond 44 joins the polymer sheets toform a seal that prevents the fluid from escaping, tensile element 50prevents barrier 40 from expanding outward or otherwise distending dueto the pressure of the fluid. That is, tensile element 50 effectivelylimits the expansion of chamber 33 to retain an intended shape ofbarrier portions 41 and 42.

Tensile Element Manufacturing Process

A variety of manufacturing processes may be utilized to form tensileelement 50. FIG. 9 depicts a spacing structure 100 suitable for use informing tensile element 50. Spacing structure 100 includes a firstsurface 101, which may be an upper surface, and an opposite secondsurface 102, which may be a lower surface. In addition, a number of sidesurfaces 103 that extend between first surface 101 and second surface102. Spacing structure 100 includes a plurality of support portions 104separated by a plurality of gaps 105. In some configurations, asdepicted in FIG. 9, spacing structure 100 may have a comb-likeconfiguration, with support portions 104 extending in a substantiallyaligned and parallel direction that resembles the fingers of a comb.

In various manufacturing processes, first material layer 51, secondmaterial layer 52, and spacing structure 100 may be stacked.Subsequently, in a stitching step (which may be performed by a sewing orstitching machine, by hand, or by another method of forming stitches),one or more strands of material that form strand segments 53 may be usedto join the first material layer to the second material layer, therebyforming tensile element 50 from first material layer 51, second materiallayer 52, and the strand or strands.

Depending upon the particular manufacturing process, spacing structure100 may be removed after the stitching step, and first material layer 51may be spaced from second material layer 52. Once material layers 51 and52 are spaced from each other, various pluralities of strand segments 53are positioned throughout tensile element 50. Strand segments 53 aresegments of the material strand or strands stitched through materiallayers 51 and 52. Some strand segments 53 extend between material layers51 and 52. Other strand segments 53 extend across outwardly-facingsurfaces of material layers 51 and 52. Similarly, a plurality of rows 54of strand segments 53, corresponding with adjacent, contiguous stitchesor segments of the same strand, are positioned throughout tensileelement 50.

As an example, FIGS. 10A-10D schematically depict steps in a process formanufacturing tensile element 50. As depicted in FIG. 10A, materiallayers 51 and 52 and spacing structure 100 are stacked such that spacingstructure 100 is located between first material layer 51 and secondmaterial layer 52. A needle 111 stitches, sews, or otherwise draws astrand 110 from a spool 120, through first material layer 51, through agap 105 between support portions 104, and through second material layer52. Strand 110 is then stitched, sewn, or otherwise drawn back throughsecond material layer 52, gap 105, and first material layer 51. Needle111 is then moved to a nearby position on first material layer 51 anddrawn in another loop, course, or stitch back through material layers 51and 52, and so on, until a row 54 of strand segments 53 extends acrosstensile element 50, as depicted in FIG. 10B. First material layer 51 andsecond material layer 52 may accordingly be joined by a row 54 of strandsegments 53 or stitches. Although depicted as being stitched insubstantially the same direction in which support portions 104 and gaps105 extend, in other configurations, strand 110 may be stitched in adirection substantially perpendicular to or angled with respect to thedirection in which support portions 104 and gaps 105 extend. That is,rows 54 may extend across one or more support portions 104 and through aplurality of gaps 105.

As depicted in FIG. 10C, the stitching of strand 110 has been completed,forming additional rows 54 of strand segments 53 or stitchescorresponding with the remaining gaps 105. Rows 54 of strand segments 53accordingly extend throughout each gap 105. Each of rows 54 may beformed from a separate or distinct portion of strand 110. Alternatively,strand 110 may extend across a support portion 104 at the end of one row54 and form the beginning of another row 54, such that some or all ofrows 54 may be formed from a single, contiguous portion of strand 110.Thereafter, as depicted in FIG. 10D, spacing structure 100 is removed,and tensile element 50 is provided with a plurality of strand segments53 that extend between material layers 51 and 52.

As another example, FIGS. 11A-11F schematically depict steps in anotherprocess for manufacturing tensile element 50. As depicted in FIG. 11A,first material layer 51 and second material layer 52 are stacked, withfirst material layer 51 being in contact with second material layer 52.Material layers 51 and 52 are then stacked with spacing structure 100such that first material layer 51 is located between second materiallayer 52 and spacing structure 100, i.e., such that both material layers51 and 52 are on the same side of spacing structure 100. Needle 111 thenstitches, sews, or otherwise draws strand 110 from spool 120, through agap 105 between support portions 104, through first material layer 51,and through second material layer 52. Strand 110 is then stitched, sewn,or otherwise drawn back through second material layer 52, first materiallayer 51, and the gap 105, creating a stitch joining first materiallayer 51 and second material layer 52, as depicted in FIG. 11B. Needle111 is then moved over a support portion 104, positioned at an adjacentgap 105, and drawn in another loop, course, or stitch back throughmaterial layers 51 and 52 and over another support portion 104, and soon, until a row 54 of strand segments 53 or stitches extends across aplurality of support portions 104, as depicted in FIG. 11C. Strand 110has been stitched in a direction substantially perpendicular to thedirection in which support portions 104 and gaps 105 extend. That is,rows 54 primarily extend through a plurality of gaps 105 and a pluralityof support portions 104.

As depicted in FIG. 11D, the stitching of strand 110 has been completed,forming multiple rows 54 of strand segments 53 extending both acrosssupport portions 104 and through gaps 105 between support portions 104.Each of rows 54 may be formed from a separate or distinct portion ofstrand 110, or some or all of rows 54 may be formed from a single,contiguous portion of strand 110. Thereafter, as depicted in FIG. 11E,spacing structure 100 is removed. At this stage, portions of strand 110form loops. First material layer 51 is then spaced from second materiallayer 52, as depicted in FIG. 11F, to provide tensile element 50 with aplurality of strand segments 53 positioned to extend between materiallayers 51 and 52.

Strand 110 (and, in turn, portions of strand 110 such as strand segments53) may be formed to include any of a variety of materials and may haveany of a variety of generally one-dimensional structures. As utilizedherein, the term “one-dimensional structure” or variants thereof isintended to encompass generally elongate structures exhibiting a lengththat is substantially greater than a width and a thickness. Thethickness of strand 110 may vary significantly to range from less than0.03 millimeters to more than 5 millimeters, for example. Althoughone-dimensional structures will often have a cross-section where widthand thickness are substantially equal (e.g., a round or squarecross-section), some one-dimensional structures may have a width that isgreater than a thickness (e.g., a rectangular, oval, or otherwiseelongate cross-section). Despite the greater width, a structure may beconsidered one-dimensional if a length of the structure is substantiallygreater than a width and a thickness of the structure.

Suitable materials for strand 110 include rayon, nylon, polyester,polyacrylic, silk, cotton, carbon, glass, aramids (e.g., para-aramidfibers and meta-aramid fibers), ultra high molecular weightpolyethylene, liquid crystal polymer, copper, aluminum, and steel.Suitable generally one-dimensional structures for strand 110 includefilaments, fibers, yarns, threads, cables, or rope. Whereas filamentshave an indefinite length and may be utilized individually as strands,fibers have a relatively short length and generally go through spinningor twisting processes to produce a strand of suitable length. Anindividual filament utilized in strand 110 may be formed form a singlematerial (i.e., a monocomponent filament) or from multiple materials(i.e., a bicomponent filament). In addition, different filaments may beformed from different materials. As an example, yarns utilized as strand110 may include filaments that are each formed from a common material,may include filaments that are each formed from two or more differentmaterials, or may include filaments that are each formed from two ormore different materials. Yarns utilized as strand 110 may also includeindividual fibers formed from a single material, individual fibersformed from multiple materials, or different fibers formed fromdifferent materials. Similar concepts also apply to threads, cables, orropes.

Material layers 51 and 52 may be formed of, or may be formed to include,a variety of materials. Material layers 51 and 52 may be formed toinclude various types of textiles, such as knitted textiles, woventextiles, non-woven textiles, spacer textiles, or mesh textiles, and mayinclude various types of materials, such as rayon, nylon, polyester,polyacrylic, elastane, cotton, wool, or silk. The textiles may besubstantially non-stretch, or may exhibit significant one-dimensionalstretch, or may exhibit significant multi-directional stretch. Materiallayers 51 and 52 may also be formed to include supplemental polymerlayers, polymer sheets, or synthetic leather, for example. Additionally,either of material layers 51 and 52 could be formed of combinations ofmaterials, such as composite layers including both a textile material orlayer and a polymer material or sheet.

Fluid-Filled Chamber Manufacturing Process

Although a variety of manufacturing processes may be utilized to formchamber 33, an example of a suitable thermoforming process will now bediscussed. With reference to FIG. 12, a mold 60 that may be utilized inthe thermoforming process is depicted as including a first mold portion61 and a second mold portion 62. Mold 60 is utilized to form chamber 33from a pair of polymer sheets that are molded and bonded to definebarrier portions 41 and 42 as well as peripheral edge 43, and thethermoforming process secures tensile element 50 within barrier 40. Moreparticularly, mold 60 (a) imparts shape to one of the polymer sheets inorder to form first barrier portion 41, (b) imparts shape to the otherof the polymer sheets in order to form second barrier portion 42, (c)imparts shape to one or both of the polymer sheets in order to formperipheral edge 43, (d) joins and seals the polymer sheets at peripheralbond 44, and (e) bonds tensile element 50 to each of barrier portions 41and 42.

In preparation for the manufacturing process, various components formingchamber 33 may be obtained and organized. For example, tensile element50 may be formed and, if necessary, cut to a shape generallycorresponding with the shapes of various features of mold portions 61and 62. A first polymer sheet 71 and a second polymer sheet 72 may beused to form barrier 40. Tensile element 50 may be positioned betweenfirst polymer sheet 71 and second polymer sheet 72. Upon completion ofthe manufacturing process, when chamber 33 is pressurized, tensileelement 50 is placed in tension and barrier portions 41 and 42, formedfrom polymer layers 71 and 72, are spaced from each other.

In manufacturing chamber 33, the various components of chamber 33 arelocated between mold portions 61 and 62, as depicted in FIGS. 13A and14A. In order to properly position the components, a shuttle frame orother device may be utilized. Subsequently, the various components ofchamber 33 are heated to a temperature that facilitates bonding betweenthe components. Depending upon the specific materials utilized fortensile element 50 and polymer sheets 71 and 72, which form barrier 40,suitable temperatures may range from 120 to 200 degrees Celsius (248 to392 degrees Fahrenheit) or more. Various radiant heaters or otherdevices may be utilized to heat the various components of chamber 33. Insome manufacturing processes, mold 60 may be heated such that contactbetween mold 60 and the various components of chamber 33 raises thetemperature of the components to a level that facilitates bonding. Inalternate manufacturing processes, the various components of chamber 33,such as one or more of polymer sheets 71 and 72 and tensile element 50,may be heated before being located between mold portions 61 and 62.

Once the various components of chamber 33 are positioned and heated,mold portions 61 and 62 translate toward each other and begin to closeupon the components such that (a) first mold portion 61 contacts firstpolymer sheet 71, and (b) ridge 64 of second mold portion 62 contactssecond polymer sheet 72. In turn, first polymer sheet 71 may be broughtcloser to first material layer 51 of tensile element 50, and polymerlayer 72 may be brought closer to second material layer 52 of tensileelement 50. The components are thus located relative to mold 60 andinitial shaping and positioning has occurred.

Air may then be partially evacuated from the area around polymer sheets71 and 72 through various vacuum ports in mold portions 61 and 62. Thepurpose of evacuating the air is to draw polymer sheets 71 and 72 intocontact with the various contours of mold 60. This ensures that polymersheets 71 and 72 are properly shaped in accordance with the contours ofmold 60. Note that polymer sheets 71 and 72 may stretch in order toextend around tensile element 50 and into mold 60. The thickness ofpolymer sheets 71 and 72 before being compressed between mold portions61 and 62 may be greater than the thickness of the correspondingportions of barrier 40 after the manufacture of chamber 33 has beencompleted. This difference between the original thicknesses of polymersheets 71 and 72 and the resulting thickness of barrier 40 may occur asa result of the stretching taking place at this stage of thethermoforming process.

Mold portions 61 and 62 may compress and place a specific degree ofpressure upon the components, thereby bonding and securing polymersheets 71 and 72 to opposite surfaces of tensile element 50. Morespecifically, first polymer sheet 71 may be thermobonded to firstmaterial layer 51 of tensile element 50. Similarly, second polymer sheet72 may be thermobonded to second material layer 52 of tensile element50. Second mold portion 62 includes a peripheral cavity 63 that formsperipheral edge 43 from second polymer layer 72. As depicted in FIGS.12-14D, polymer sheets 71 and 72 are thermobonded to tensile element 50,but in other manufacturing processes, polymer sheets 71 and 72 may atleast partially be otherwise secured to tensile element 50. For example,polymer sheets 71 and 72 may at least partially be secured to tensileelement 50 by an adhesive, or by use of thermoplastic threads or strips,as disclosed in U.S. Pat. No. 7,070,845 to Thomas, et al.

As utilized herein, the term “thermobonding” or variants thereof isdefined as a securing technique between two elements that involves asoftening or melting of a thermoplastic polymer material within at leastone of the elements such that the materials of the elements are securedto each other when cooled. Similarly, the terms “thermobond” or variantsthereof is defined as the bond, link, or structure that joins twoelements through a process that involves a softening or melting of athermoplastic polymer material within at least one of the elements suchthat the materials of the elements are secured to each other whencooled. Thermobonding may involve, for example, the melting or softeningof thermoplastic materials within each of two or more elements to jointhe elements. Accordingly, thermobonding may create a polymer bond(i.e., a thermobond between a polymer material of one element and apolymer material of another element).

Thermobonding does not generally involve the use of stitching oradhesives, but involves directly bonding elements to each other withheat. In some situations, however, stitching or adhesives may beutilized to supplement the thermobond or the joining of elements throughthermobonding. For example, as an alternative to thermobonding, or inaddition to thermobonding, an adhesive, a thermally-activated adhesive,or other securing structure may be utilized in joining the elements.

As mold 60 closes further, first mold portion 61 and ridge 64 bond firstpolymer sheet 71 to second polymer sheet 72, as depicted in FIGS. 13Band 14B, thereby forming peripheral bond 44 and an interior void betweenpolymer sheets 71 and 72. Furthermore, portions of ridge 64 that extendaway from tensile element 50 form a bond between other areas of polymersheets 71 and 72, contributing to the formation of an inflation conduit73.

In order to provide another means for drawing polymer sheets 71 and 72into contact with the various contours of mold 60, the area betweenpolymer sheets 71 and 72 and proximal to tensile element 50 may bepressurized. During a preparatory stage of this method, an injectionneedle may be located between polymer sheets 71 and 72, and theinjection needle may be located such that ridge 64 envelops theinjection needle when mold 60 closes. A gas may then be ejected from theinjection needle such that polymer sheets 71 and 72 engage ridge 64.Inflation conduit 73 may thereby be formed between polymer sheets 71 and72 (see FIG. 13C). The gas may then pass through inflation conduit 73,thereby entering and pressurizing the area proximal to tensile element50 and between polymer sheets 71 and 72. In combination with the vacuum,the internal pressure ensures that polymer sheets 71 and 72 contact thevarious surfaces of mold 60.

As discussed above, a supplemental layer of a polymer material orthermoplastic threads may be added to or incorporated within tensileelement 50 in order to facilitate bonding between tensile element 50 andbarrier 40. The pressure exerted upon the components by mold portions 61and 62 may ensure that the supplemental layer or thermoplastic threadsform a bond with polymer sheets 71 and 72.

When bonding is complete, mold 60 is opened and the various componentsof chamber 33 and excess portions of polymer sheets 71 and 72 arepermitted to cool, as depicted in FIGS. 13C and 14C. A fluid may beinjected into the interior void through an inflation needle andinflation conduit 73. Upon exiting mold 60, tensile element 50 remainsin a compressed configuration. When the various components of chamber 33are pressurized, however, the fluid places an outward force upon barrier40, which tends to separate barrier portions 41 and 42, thereby placingtensile element 50 in tension. More specifically, strand segments 53extending between first material layer 51 and second material layer 52are placed in tension, as is the portion of strand 110 comprising allthe strand segments 53 of a particular row 54.

In addition, a sealing process is utilized to seal inflation conduit 73after pressurization. The excess portions of polymer sheets 71 and 72are then removed, thereby completing the manufacture of chamber 33, asdepicted in FIGS. 13D and 14D. As an alternative, the order of inflationand removal of excess material may be reversed. Finally, chamber 33 maybe tested and then incorporated into midsole 31 of footwear 10.

Further Configurations

Although chamber 33 is described above and depicted in FIGS. 4-8C, andalthough various exemplary processes for manufacturing tensile element50 are described above and depicted in FIG. 9-11F, these configurationsof chamber 33 and processes for manufacturing tensile element 50 areinitial configurations. Other configurations are possible. For example,as depicted in FIGS. 15A-18C, spacing structure 100 and tensile element50 may have a range of configurations. For example, as depicted in FIGS.15A and 15B, spacing structure 100 may have any of a variety of heights,such as the relatively taller height depicted in FIG. 15A, or therelatively shorter height depicted in FIG. 15B. Similarly, althoughdepicted as extending beyond first material layer 51 and second materiallayer 52 in FIGS. 9-11F, spacing structure 100 may have any of a rangeof widths or lengths, including a width shorter than or substantiallyequal to the width of material layer 51 or 52, or a length shorter thanor substantially equal to the length of material layer 51 or 52.

Additionally, spacing structure 100 is depicted in FIGS. 9-11F as havinga comb-like structure bounded by a substantially rectangular shape. Invarious other configurations, spacing structure 100 may be bounded byany of a range of shapes, including regular geometric shapes such assquares, circles, triangles, and hexagons, as well as any other shape,regular or irregular, including shapes corresponding with alternateportions of a foot. Similarly, although depicted as having a shapesimilar to heel region 13 of footwear 10, material layers 51 and 52 mayhave any of a range of shapes, including regular geometric shapes aswell as any other shape, regular or irregular, including shapescorresponding with alternate portions of a foot.

As depicted in FIGS. 9-11F, spacing structure 100 has support portions104 and gaps 105 that are substantially linear and have substantiallyuniform width. However, support portions 104 and gaps 105 may beotherwise configured. For example, as depicted in FIG. 15C, supportportions 104 and gaps 105 may be substantially curved. Furthermore, asdepicted in FIG. 15D, support portions 104 and gaps 105 may havenon-uniform width, such that their width near one side of spacingstructure 100 is substantially greater than their width near an oppositeside of spacing structure 100.

In the comb-like structure depicted in FIGS. 9-11F, all the supportportions 104 of spacing structure 100 extend away from a side of spacingstructure 100, such that spacing structure 100 has a unitary orone-piece configuration. Other configurations of spacing structure 100are possible. For example, spacing structure 100 in FIG. 15E has atwo-piece configuration including two portions resembling comb-likestructures having interlocking fingers. In other words, some supportportions 104 of spacing structure 100 may be part of one unitary orone-piece portion of spacing structure 100, whereas other supportportions 104 of spacing structure 100 may be part of another unitary orone-piece portion of spacing structure 100. Accordingly, in variousconfigurations, support portions 104 of spacing structure 100 mayinclude any number of unitary or one-piece portions. In an alternateexample depicted in FIG. 15F, spacing structure 100 includes supportportions 104 that extend away from a side of a unitary or one-pieceportion of spacing structure 100, and spacing structure 100 alsoincludes a plurality of support portions 104 that are self-containedunitary or one-piece portions of spacing structure 100.

Furthermore, although depicted in FIGS. 9-11F as having a substantiallyuniform height, spacing structure 100 as well as support portions 104and gaps 105 may have non-uniform heights that may impart a non-uniformcontour to spacing structure 100, and may accordingly also impart anon-uniform structure to tensile element 50. For example, as depicted inFIG. 15G, spacing structure 100 has a greater height at a first end thanat a second end, and substantially linearly decreases in height from thefirst end to the second end, which imparts a substantially lineardecrease in height to support portions 104 and gaps 105. Accordingly, asdepicted in FIG. 15G, spacing structure 100 may impart a taperedconfiguration to tensile element 50. As a further example, as depictedin FIG. 15H, spacing structure 100 includes two one-piece or unitaryportions, each portion having a comb-like configuration, and the fingersof the two comb-like portions extending away from a side of each portionand toward each other. The two comb-like portions of spacing structure100 cooperatively define a depression within first surface 101 ofspacing structure 100. Accordingly, as depicted in FIG. 15H, spacingstructure 100 may impart a heel cup to tensile element 50, as depictedin cross-section in FIG. 17A. Similarly, in various configurations,first surface 101, second surface 102, and side surfaces 103 of spacingstructure 100 may have any of a variety of non-planar contours, whichmay in turn impart corresponding non-planar contours to tensile element50.

FIGS. 9-11F depict each of material layers 51 and 52 as having unitaryor one-piece configurations. However, in further configurations,material layers 51 and 52 may be otherwise configured to have any numberof unitary or one-piece portions. For example, as depicted in FIG. 16A,first material layer 51 is depicted as having two one-piece portions,whereas second material layer 52 is depicted as having three one-pieceportions. In various configurations, either material layer 51 or 52 mayhave any of a number of one-piece portions, each of which may have anyof a range of shapes, including regular geometric shapes as well as anyother shape, regular or irregular.

Although FIG. 10D depicts spacing structure 100 as having been removed,portions of spacing structure 100, or all of spacing structure 100, mayremain within tensile element 50. For example, as depicted FIG. 16B, aplurality of remainder portions 106 of spacing structure 100 (which hasbeen formed to include a foam material) have been left within tensileelement 50. As a further example, FIG. 16C depicts alternate remainderportions 106 that have been left within tensile element 50, eachremainder portion 106 being a peripheral or outer part of each ofsupport portions 104.

In FIGS. 4-8C, tensile element 50 has strand segments 53 configured toextend between first material layer 51 and second material layer 52 in aparticular way. However, in various configurations, strand segments 53may extend between material layers 51 and 52 in other ways. For example,strand segments 53 within a particular row 54 may be relatively lessdensely packed, as depicted in FIG. 17B, or may be relatively moredensely packed, as depicted in FIG. 17C. Moreover, although FIGS. 4-8Cdepict five rows 54 of strand segments 53 spanning tensile element 50,different numbers of rows 54 may span tensile element 50. For example,FIG. 18A depicts three relatively less densely packed rows 54 spanningtensile element 50, whereas FIG. 18B depicts nineteen relatively moredensely packed rows 54 spanning tensile element 50.

FIGS. 9-11F depict tensile element 50 as being formed using a relativelysimple stitching technique, such as a running stitch technique. However,in various configurations of the manufacturing process, a variety ofstitching or sewing techniques may be employed, by hand or by machine,such as a double running stitching technique, a lockstitching technique,an overlock stitching technique, or any other stitching technique.Additionally, depending upon the stitching technique used, more than onestrand 110 or portion of strand 110 may be used to form the stitches ina particular row 54. For example, as depicted in FIG. 17D, two portionsof strand 110 are used to form row 54 of stitches, an additional strand110 forms stitches that complement the first strand 110. As depicted,both strands 110 are in tension, and each strand 110 extends throughboth first material layer 51 and second material layer 52.

Alternatively, as depicted in FIG. 17E, one strand 110 extends throughonly first material layer 51, and another strand 110 extends throughonly second material layer 52. Both strands 110 are interlocked witheach other in the interior void of chamber 33, between material layers51 and 52, and may thereby be placed in tension upon pressurization ofchamber 33. Various stitching techniques are also possible in otherconfigurations of the manufacturing process. For example, FIG. 17Fdepicts an alternate simple stitching or sewing technique, and FIG. 17Gdepicts a technique in which first material layer 51 is joined to secondmaterial layer 52 with a plurality of strands, and a separate strand isused to form each of a plurality of stitches.

Additionally, although tensile element 50 and barrier 40 are depicted asbeing separate elements, they may be more integrally related in someconfigurations of the manufacturing process. For example, as depicted inFIG. 18C, the material used for first material layer 51 is first polymersheet 71, and the material used for second material layer 52 is secondpolymer sheet 72. In this configuration, part or all of first barrierportion 41 is first material layer 51, and part or all of second barrierportion 42 is second material layer 52. Accordingly, various pluralitiesof strand segments 53 may extend (a) across an outward-facing surface offirst barrier portion 41, and (b) across an outward-facing surface ofsecond barrier portion 42.

The invention is disclosed above and in the accompanying figures withreference to a variety of configurations. The purpose served by thedisclosure, however, is to provide an example of the various featuresand concepts related to the invention, not to limit the scope of theinvention. One skilled in the relevant art will recognize that numerousvariations and modifications may be made to the configurations describedabove without departing from the scope of the present invention, asdefined by the appended claims.

1-20. (canceled)
 21. A method of manufacturing a tensile element, themethod comprising: locating a spacing structure between a first materiallayer and a second material layer, at least one of the first materiallayer and the second material layer including a first portion separatedfrom a second portion by a void that extends across a width of the atleast one of the first material layer and the second material layer;stitching through the spacing structure with at least one strand to jointhe first material layer to the second material layer to form thetensile element from the first material layer, the second materiallayer, and the strand; and maintaining a portion of the spacingstructure between the first material layer and the second material layerafter formation of the tensile element.
 22. The method of claim 21,further comprising forming at least one of the first material layer andthe second material layer from a textile.
 23. The method of claim 21,wherein locating a spacing structure between the first material layerand the second material layer includes locating a spacing structureformed from foam.
 24. The method of claim 21, wherein locating a spacingstructure between the first material layer and the second material layerincludes locating a hollow structure between the first material layerand the second material layer.
 25. The method of claim 21, whereinlocating a spacing structure between the first material layer and thesecond material layer includes providing a spacing structure having aplurality of support portions separated by a plurality of gaps.
 26. Themethod of claim 25, wherein stitching through the spacing structure withat least one strand includes stitching within the gaps between adjacentsupport portions of the plurality of support portions.
 27. The methodclaim 25, further comprising providing at least one of the plurality ofgaps with a taper.
 28. The method of claim 25, further comprisingproviding at least one of the plurality of gaps with a constant widthalong the length of the at least one of the plurality of gaps.
 29. Themethod of claim 25, further comprising extending a portion of thestitching over at least one of the plurality of support portions. 30.The method of claim 25, wherein maintaining a portion of the spacingstructure between the first material layer and the second material layerafter formation of the tensile element includes maintaining at least onesupport portion of the plurality of support portions between the firstmaterial layer and the second material layer.
 31. A method ofmanufacturing a tensile element, the method comprising: locating aspacing structure between a first material layer and a second materiallayer, at least one of the first material layer and the second materiallayer including a first portion separated from a second portion by avoid that extends across a width of the at least one of the firstmaterial layer and the second material layer; stitching through thespacing structure with at least one strand to join the first materiallayer to the second material layer to form the tensile element from thefirst material layer, the second material layer, and the strand; andseparating a first portion of the spacing structure from a secondportion of the spacing structure after formation of the tensile element.32. The method of claim 31, further comprising forming at least one ofthe first material layer and the second material layer from a textile.33. The method of claim 31, wherein locating a spacing structure betweenthe first material layer and the second material layer includes locatinga spacing structure formed from foam.
 34. The method of claim 31,wherein locating a spacing structure between the first material layerand the second material layer includes locating a hollow structurebetween the first material layer and the second material layer.
 35. Themethod of claim 31, wherein locating a spacing structure between thefirst material layer and the second material layer includes providing aspacing structure having a plurality of support portions separated by aplurality of gaps.
 36. The method of claim 35, wherein stitching throughthe spacing structure with at least one strand includes stitching withinthe gaps between adjacent support portions of the plurality of supportportions.
 37. The method claim 35, further comprising providing at leastone of the plurality of gaps with a taper.
 38. The method of claim 35,further comprising providing at least one of the plurality of gaps witha constant width along the length of the at least one of the pluralityof gaps.
 39. The method of claim 35, further comprising extending aportion of the stitching over at least one of the plurality of supportportions.
 40. The method of claim 35, wherein extending a portion of thestitching over at least one of the plurality of support portionsincludes stitching in two different gaps located on opposite sides ofthe same one of the plurality of support portions.
 41. The method ofclaim 31, further comprising maintaining the first portion of thespacing structure between the first material layer and the secondmaterial layer after formation of the tensile element.